you mention you app 'should' work on 4.4.2, but have you managed to try it - or know of someone who has?

I ask since I'm currently on 4.2.2 OmegaRom v12 and cannot get the phone to link with my Audi MMI via anything other than Handsfree mode, and your phonebook app. Your rsap app does not do the trick for me.

On another note, is the rsap functionality based in the firmware, modem, kernel or actual software - I ask since I might try a different firmware/modem/kernel if possible?

**I managed to trip the knox counter with all this messing around getting things to work, so if I do move to 4.4.2 I can't move back, hence want to check**

I fell foul of knox so I'm not sure if I should try to go back to stock ROM (and probably be stuck on 4.2), or keep a custom rom and upgrade to 4.4.2, including upgrading the bootloader, which then I think means I can't go back to stock? I need to keep searching on that one..

as you mention the modem though, that might be my chance - I can flash that with Odin. I'm currently on I9505XXUEMJ5, so there may be some options for me..

I'll update this thread once I figure out what I can do without bricking the phone

I don't think playing with different modem versions helps. All S4 modems should support rSAP and they should support it with stock ROM and all ROMs based on stock, i.e. not based on CyanogenMod or Google Edition. Are you sure your Audi supports rSAP?

it's a 2014 Audi, and I did see the salesman in the showroom - when I was collecting the car - walk me through the phone setup, and it picked up his phone and offered WLAN, google etc. so pretty sure it's on there, just not available for me..

I can't downgrade either - so I think I will be back on 4.2.2, and it seems rSAP stopped after 4.2?

I currently have a phone, which when receiving a call turns the screen black, so it seems something else has gone funny with the recovery..

My options left (probably all without rsap):
1. recover the phone somehow - leaving it on OmegaRom v12 android 4.2.2
2. recover as above and flash back to stock - not even sure if this is still possible
3. wonder why I bothered with Samsung in the first place

I guess the best idea is to flash a stock ROM. You only have to choose which version, because for 4.3 and 4.4 there is no way back. But why should you want to go back...?

Before you do anything you may create a HCI log, either in the developer settings in 4.4 or with my logger app, and mail it to admin at... So I can check if the car really tries to access rSAP and why it fails.